Well-established power distribution systems exist throughout most of the United States, and other countries, which provide power to customers via power lines. With some modification, the infrastructure of the existing power distribution systems can be used to provide data communication in addition to power delivery, thereby forming a power line communication system (PLCS). In other words, existing power lines, that already have been run to many homes and offices, can be used to carry data signals to and from the homes and offices. These data signals are communicated on and off the power lines at various points in the power line communication system, such as, for example, near homes, offices, Internet service providers, and the like.
Power distribution systems include numerous sections, which transmit power at different voltages. The transition from one section to another typically is accomplished with a transformer. The sections of the power distribution system that are connected to the customers premises typically are low voltage (LV) sections having a voltage between 100 volts (V) and 200V, depending on the system. In the United States, the LV section typically is about 120V. The sections of the power distribution system that provide the power to the LV sections are referred to as the medium voltage (MV) sections. The voltage of the MV section is in the range of 1,000V to 100,000V. The transition from the MV section to the LV section of the power distribution system typically is accomplished with a distribution transformer, which converts the higher voltage of the MV section to the lower voltage of the LV section.
In one example PLCS embodiment, a backhaul point forms the gateway between the power line and conventional telecommunications medium and communicates with a plurality of downstream communication devices such as transformer bypass devices. The backhaul point and its plurality of communication devices (and their associated user devices) form a PLCS subnet.
In a PLCS the low voltage power line typically has the highest noise and interference that limits the amount of data that can be transmitted over the low voltage power line. This problem is more acute when multiple users are all sharing the same low voltage power line subnet. Therefore, there remains a need to prove additional and alternate bandwidth capability to a user of a PLCS. Further, the users of other types of broadband systems may have service outages. For example, if a user has a DSL connection that has an outage, the user is unable to communicate with the internet or other external network. For many users such an outage may result in various detrimental effects such as work stoppage, loss of E-mail capability, etc. Therefore there remains a need for a backup capability in the case of such outages.